TY - JOUR
T1 - How hot is the wire
T2 - Optical, electrical, and combined methods to determine filament temperature
AU - Onnink, Arnoud J.
AU - Schmitz, Jurriaan
AU - Kovalgin, Alexey Y.
PY - 2019/3/31
Y1 - 2019/3/31
N2 - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.
AB - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.
KW - Emittance
KW - Filament temperature
KW - Hot-wire assisted chemical vapor deposition
KW - Planck's law
KW - Pyrometry
KW - Radiation thermometry
KW - Resistance thermometry
KW - Resistivity
UR - http://www.scopus.com/inward/record.url?scp=85061081733&partnerID=8YFLogxK
U2 - 10.1016/j.tsf.2019.02.003
DO - 10.1016/j.tsf.2019.02.003
M3 - Article
AN - SCOPUS:85061081733
VL - 674
SP - 22
EP - 32
JO - Thin solid films
JF - Thin solid films
SN - 0040-6090
ER -